I totally agree with both things you wrote above here: they wanted to punish her but harmed you instead - not good.
It is totally confusing when someone tells you therapy is a "safe harbour" then makes it unsafe. I went through that and would not go back to therapy with an agency because the management hierarchy seem to be unaccountable.

Can you write them a letter simply saying what you wrote above? You don't have to do that if it's too painful, but if something is wrong sometimes it feels ok to speak up and ask for an apology.